Engineers at the University of Ulster are the first researchers to create diamond nanorods with a diameter as thin as 2.1 nm, which is not only smaller than all the currently reported diamond 1D nanostructures (4-300 nm) but also smaller than the theoretical calculated value (2.7-9 nm) for energetically stable diamond nanorods.

This is only twice as wide as the “rod logic” rods in Nanosystems. These are still bulk technology, though, and not atomically precise. Near-term uses seem to be as low-power cold cathodes and the like. See also here and here.